This paper reviews the main advances of our group on the measurements of the diffusion coefficient through partially saturated porous materials. The technique that we developed is based on the definition of an equivalent electrical model reproducing the behavior of the porous microstructure. The electrical characteristics are measured by means of Electrochemical Impedance Spectroscopy. After validating the approach on saturated samples, the method was applied to partially saturated materials. We showed that the pore solution ionic composition has not impact on the results, and documented the effect of the pore size distribution on the macroscopic diffusion coefficient.